The conventional method for elevator construction inside a building (such as by rail guiding or piping wiring) is to first construct a scaffold within the elevator room that allows the construction worker to maneuver and transport equipment. However, the scaffold construction not only take long time to complete, but also when the project is completed, the scaffold would need to be taken down, thus not only economical inefficient but also time consuming. Therefore, many elevator construction process or machinery that does not use the scaffold is being invented to replace the conventional elevator construction method.
No matter what type of construction method, the main machinery used for elevator construction is by a winding machine guiding a main suspension cable of an elevating work platform. In order to maintain balance of the elevating work platform, there are usually additional supporting suspension cables connected to the elevating work platform to guide and avoid the spinning rotation of the elevating work platform. Of course, base on different construction conditions, the elevator guide rails that are already installed can also be used to replace the additional supporting suspension cable.
In the construction business, one can never be too cautious because there is just no minor accident in this field. In order to prevent the chance of falling elevating work platform due to brake of the main suspension cable or failure of the winding machine, all the elevating work platforms are provided with the conventional braking arrangement. The conventional braking arrangement comprises a breaking unit to be engaged with each additional supporting suspension cables, a centering gear, and an eccentric uni-direction ratchet is coaxially provided in respect to the braking unit, wherein the eccentric uni-direction ratchet is for locking onto the additional supporting suspension cables and the centering gear is engaged with a rack of the main suspension cable, where a bottom side of the rack is connected to a flexible material.
When the main suspension cable is broken, the flexible material provided the rack a downward pulling force, which driven the centering gear and the eccentric uni-direction ratchet to locking onto the additional supporting suspension cables. Although the above describe mechanism can accomplish the design function, however, it does not provided braking function while the elevating work platform is moving to certain position. The function of the above describe mechanism is only limited to when the main suspension cable is broken, and the braking arrangement can provide emergency stop. In the situation when the break of the winding machine is malfunctioned, the elevating work platform would not be able to stop but fall down because the conventional braking arrangement is not designed to protect against such condition. Furthermore, the eccentric uni-direction ratchet that locked on the additional supporting suspension cables would alter the original form of the cables, thus make the cables become useless. Also if the guide rails were used to replace the additional supporting suspension cables, the conventional braking arrangement would not be able to provide service.